/*
   Memsic2125
   
   Read the Memsic 2125 two-axis accelerometer.  Converts the
   pulses output by the 2125 into milli-g's (1/1000 of earth's
   gravity) and prints them over the serial connection to the
   computer.
   
   The circuit:
	* X output of accelerometer to digital pin 2
	* Y output of accelerometer to digital pin 3
	* +V of accelerometer to +5V
	* GND of accelerometer to ground
  
   http://www.arduino.cc/en/Tutorial/Memsic2125
   
   created 6 Nov 2008
   by David A. Mellis
   modified 30 Jun 2009
   by Tom Igoe

 */

// these constants won't change:
const int xPin = 6;		// X output of the accelerometer
const int yPin = 7;		// Y output of the accelerometer
const int zPin = 4;		// Y output of the accelerometer

void setup() {
  // initialize serial communications:
  Serial.begin(9600);
  // initialize the pins connected to the accelerometer
  // as inputs:
  pinMode(xPin, INPUT);
  pinMode(yPin, INPUT);
}

void loop() {
  // variables to read the pulse widths:
  int pulseX, pulseY;
  // variables to contain the resulting accelerations
  int accelerationX, accelerationY;
  
  // read pulse from x- and y-axes:
  pulseX = pulseIn(xPin,HIGH);  
  pulseY = pulseIn(yPin,HIGH);
  
  // convert the pulse width into acceleration
  // accelerationX and accelerationY are in milli-g's: 
  // earth's gravity is 1000 milli-g's, or 1g.
  accelerationX = ((pulseX / 10) - 500) * 8;
  accelerationY = ((pulseY / 10) - 500) * 8;
  
  
  // x = -1000 to 1000
  accerlationX = limit(accelerationX);
  int blue = map(accelerationX, -1200, 1200, 0, 1023);
  int green = map(accelerationY, -1200, 1200, 0, 1023);
  
  
  // print the acceleration
  Serial.print(accelerationX);
  Serial.print("\t");
  Serial.print(accelerationY);
  Serial.println();

  delay(100);
}

void limit(int value) {
  if (value > 1200) {
    return 1200;
  } else if (value < -1200) {
    return -1200;
  }
  
  return value;
}
